Boom stop ram



" T. w. THOMAS, JR

`lune 24, 1958 BOOM STOP RAM l 2 Sheets-Sheet 1 Filed June 22. 1953INVENTOR. Thomas W Thomasldk BY @L Aff'y T. W. THOMAS, JR

June 24, 1958 BOOM STOP RAM 2 Sheets-Sheet 2 Filed June 22. 1953 l m @ia l m m em,

Unid Se@ D BOOM sror RAM Y Thomas W. Thomas, Jr., San Rafael, Calif.Appncaaan June-zz, 195s, serial No. 363,139 1 Claim. v(Cl. 21a-'39) "IThis invention relates to improvements in boom stop ram operators.

The principal object of this invention is to provide means for thecontrolling and stopping of the upward movement of a boom as used oncranes and the like load-lifting equipment.

A further object is.to provide means for gradually stopping the upwardmovement of a crane boom and to also disconnect the hoisting cable andapply the brakes at a predetermined point in the upward movement.

A further object is to produce a device of this character which may beoperated by a vacuum or mechanical means.

A further object is to produce a device which may be attached to theordinary crane without materially altering its construction.

A further object is to produce a device of this character which iseconomical to manufacture as well as simple in operation.

Other objects and advantages will be apparent during the course of thefollowing description.

In the accompanying drawings forming a part of this specification and inwhich like numbers are employed to designate like parts throughout thesame,

Fig. 1 is a side elevation of a crane having my invention appliedthereto;

Fig. 2 is an enlarged fragmentary detailed view of the operatingmechanism;

Fig. 3 is a similar view showing a modified form of my device;

Fig. 4 is a detailed view showing a mechanical means for releasing theclutch mechanism and applying the brake; v

Fig. 5 is a side elevation of the control valve; and

Fig. 6 is a vertical cross section thereof.

Cranes and the like load-lifting apparatus in most instances employ apivoted boom which is raised and lowered through the medium of a cablesecured to the top of the boom and being wound upon a driven drum.

It sometimes occurs that the operator may accidentally raise the boomtoo high or the load too high, or possibly the load line may break, thuscausing the boom to whip upwardly. When any of these conditions occur,lit is possible that the boom may be seriously damaged by crumpling overthe top of the cab, at the same time endangering the operator of thedevice.

I have therefore installed on the crane means for controlling the upwardmovement of the boom, whether such movement is intentional orunintentional, bringing the boom to a slow stop and applying brakes tothe cables so as to hold the boom in any position at which it may cometo rest. l

In the accompanying drawings, wherein for the purpose of illustration isshown a preferred embodiment of my invention, the numeral 5 designatesthe housing of a crane of standard construction having a boom 6 pivotedas at 7 and raised and lowered through the V. 2 Y y medium of a cable 8wound upon a drum 9 driven by any desired motive power.

K At 11 I have shown a brake drum about which a brake band/12 ispositioned. This brake band is controlled by a lever 13 connected to apull rod 14 which may be actuated by a hand lever 16 so as to manuallycontrol the braking of the drum 9. The construction thus far describediscommon to the average crane mechanism.

My invention consists in means for automatically retarding 'the upwardmovement of the boom and also of means for applying the brake. n

Referring to Fig. V1, it will be noted that onthe top ofthrerl housingIvhave Yshown a cylinder 17 in which Ais Vslidably'mounted a piston'18vhaving a roller 19 which is adapted to be engaged by a plate 21 mountedon the boom 6 Fig. 2. This piston 18 has a linger 20 adapted to engagethe head 26 of the piston 23, to be later described.

Within this cylinder 17 are positioned springs as described in mycompanion application Serial No. 357,129 covering a Spring Boom Stop.

Mounted on the top of the cylinder 17 is a valve cylinder 22 having asliding piston 23, normally held in extended position by a spring 24engaging the end of the cylinder 22 and a head 26 formed on the end ofthe piston 23 within the cylinder I provide a partition 27 having avalve seat against which a valve head 28 seats, this valve head beingcarried upon a reduced portion 29 of the piston 23.

A pipe 31 communicates with the interior of Ythe chamber 32 formed inthe cylinder 22 by the partition 27 and a similar pipe 33 communicateswith the chamber 34.

The pipe 31 extends from the cylinder 22 to a vacuum tank 36 in which avacuum is maintained by a suitable vacuum pump 37 driven by an engine38.

The pipe 33 connects to one side of a housing 39 in which is positioneda diaphragm which diaphragm is in turn connected to a pull rod 14.

In the Inodied form shown in Fig. 3, the construction is the same withthe exception that I have moved the cylinder to a pointcloser to thepivotal point of the boom and I have applied the same numerals thereto.

In the form shown in Fig. 4, instead of using a vacuum,

arrangement, I have installed a nger 41 on the piston 18, which has anarm 42 adapted to engage the end 43 of a rocker arm 44 pivoted as at 46'and having its opposite end connected to a pull wire 47. This wire 47 isconnected to theY lever 48 of the. master clutch 49.

The result of this construction is that when the boom moves upwardly,should the operator forget to release the clutch or should the boom whipupwardly, the following result will take place:

If the plate 21 of the boom engages the roller 19, the piston 18 willmove inwardly against the tension of the springs referred to in myprevious application. At the same time the finger 20 will engage thehead 26 of the piston'23 and will move the valve 28 ot of its seat inthe partition 27 with the result that vacuum will be caused in thechamber 34 and the pipe 33, which will draw the diaphragm in the housing39 and move the pull rod 14 toward the right of the drawing, thusapplying the brake and stopping any further upward movement of the boom.

In the modified form shown in Fig. 4, the action will be the same withthe exception that instead of employing a vacuum, the pull wire 47 willserve to disconnect the clutch mechanism and thus stop the upwardmovement of the boom.

By manipulating the lever 16, the operator can lower the boom eventhough it is holding the valve 28 open as the pressure on the diaphragmcaused by the moveaction o f the` diaphragm, thusreleasing the .brakeand allowing the boom to lower. Y

It is to be understood that 'the form of my invention herewithtshpwaand.desqribsnitg billksn. ,2S nr: ferred example of the sarne" andthatjvariou'sjchanges relative` tothe .matsriah .size Shapqalidarrangemwtfof parts ,may beybresortedr to l withoutdeparting `the spiritof theinventlion or the scope oftl 'l e` subjoined claim.

Havingthusdecribed my invention, luclaim; In `a deviceyof the characterdescribed vthe combination withalpivoted'boom andmeansmfor raising Asaidb oom together witha remotely positioned boom` holding brake, of`afsprng loaded rmrhavins. a .wing and krfillfod4 positioned inalignment with thepiyotalpathof movement of said boom, said ramlbeingmounted Aremotely from the pivotalpoint of saidiboom wherebyupwardlmovement ofsaid ,boom will engage saidwramrod 4to compress said`upward Amovement'offsaid 1 boom, a casing mountedV on said ram casing,a valve formed in said casing, a valve spring load to progressivelybuild up resistance to the :l

a finger mounted on said ramrod and adapted to engage and slide saidvalve rod to open said valve, and vacuum means controlled by said valvefor actuating said remotely located boom-holding brake to arrest furtherupward movement of said boom.

References Cited inthe tile` ofthis patent UNITED STATES PATENTS

